An overview of active control techniques for vortex rope mitigation in hydraulic turbines

S Shtork, D Suslov, S Skripkin, I Litvinov, E Gorelikov - Energies, 2023 - mdpi.com
This review addresses the current state of research into active control and suppression of
vortex rope in hydroturbines under off-design operating conditions. Only active control …

Receptivity of the turbulent precessing vortex core: synchronization experiments and global adjoint linear stability analysis

JS Müller, F Lückoff, P Paredes, V Theofilis… - Journal of Fluid …, 2020 - cambridge.org
The precessing vortex core (PVC) is a coherent structure that can arise in swirling jets from a
global instability. In this work, the PVC is investigated under highly turbulent conditions. The …

Impact of precessing vortex core dynamics on shear layer response in a swirling jet

M Frederick, K Manoharan… - … for Gas Turbines …, 2018 - asmedigitalcollection.asme.org
Combustion instability, the coupling between flame heat release rate oscillations and
combustor acoustics, is a significant issue in the operation of gas turbine combustors. This …

Phase-opposition control of the precessing vortex core in turbulent swirl flames for investigation of mixing and flame stability

F Lückoff, M Sieber… - … of Engineering for …, 2019 - asmedigitalcollection.asme.org
The precessing vortex core (PVC) is a helically shaped coherent flow structure that occurs in
reacting and nonreacting swirling flows undergoing vortex breakdown. In swirl-stabilized …

Time–frequency localisation of intermittent dynamics in a bistable turbulent swirl flame

Z Yin, M Stöhr - Journal of Fluid Mechanics, 2020 - cambridge.org
This work examines the complex flow field in a bistable turbulent swirl flame, where the
flame alternates irregularly between a lifted-off M-shape and an attached V-shape. The flow …

Excitation of the precessing vortex core by active flow control to suppress thermoacoustic instabilities in swirl flames

F Lückoff, K Oberleithner - International Journal of Spray and …, 2019 - journals.sagepub.com
In this study, we apply periodic flow excitation of the precessing vortex core at the
centerbody of a swirl-stabilized combustor to investigate the impact of the precessing vortex …

Characterization of different actuator designs for the control of the precessing vortex core in a swirl-stabilized combustor

F Lückoff, M Sieber… - … of Engineering for …, 2018 - asmedigitalcollection.asme.org
The precessing vortex core (PVC) represents a helical-shaped coherent flow structure
typically occurring in both reacting and nonreacting swirling flows. Until now, the …

The impact of heating the breakdown bubble on the global mode of a swirling jet: Experiments and linear stability analysis

L Rukes, M Sieber, CO Paschereit, K Oberleithner - Physics of Fluids, 2016 - pubs.aip.org
This study investigates the dynamics of non-isothermal swirling jets undergoing vortex
breakdown, with an emphasis on helical coherent structures. It is proposed that the …

Examining the effect of geometry changes in industrial fuel injection systems on hydrodynamic structures with biglobal linear stability analysis

TL Kaiser, K Oberleithner… - … of Engineering for …, 2020 - asmedigitalcollection.asme.org
Shape optimization with respect to the suppression or enhancement of dynamical flow
structures is an important topic in combustion research and beyond. In this paper, we …

Examining the effect of geometry changes in industrial fuel injection systems on hydrodynamic structures with biglobal linear stability analysis

TL Kaiser, K Oberleithner… - … Expo: Power for …, 2019 - asmedigitalcollection.asme.org
Shape optimization with respect to the suppression or enhancement of dynamical flow
structures is an important topic in combustion research and beyond. In this paper, we …